Evaluation of Asynchronous DS-CDMA Performance for Mobile Cellular System Applications

Abstract

Code Division Multiple Accesses (CDMA), one of the effective and efficient technologies, is used in 2nd generation (2G) , 3rd generation (3G) wireless and becomes one of potential candidates for the physical layer of 4G mobile system with the aim of improving cell capacity communication . The Bit Error Rate (BER) is considered to be one of the most important performance measures for communication systems and hence it has been extensively studied. A comprehensive analysis of the probability of error in DS-CDMA, is still an open subject.In this paper, we present a study of the bit error rate(BER) performance of an asynchronous( reverse link) DS-CDMA system over a frequency selective multipath Rayleigh fading channel, considering different techniques such as Rake Receiver with BPSK modulation and the convolutional coding of the transmitter and viterbi decoding of the receiver side. Space Division Multiple Access(SDMA) techniques were also considered in this paper by adopting a circular phase array antenna at the Mobile Base Station. Results show that the BER performance was considerably affected by the SDMA ,Convolution coding, and Rake receiver techniques.